Funding for this research was provided by:
P. Zubiaur is co-financed by Consejería de Educación, Juventud y Deporte from Comunidad de Madrid and European Social Fund.
Received: 17 October 2018
Revised: 10 September 2019
Accepted: 2 October 2019
First Online: 18 October 2019
Compliance with ethical standards
: FA-S and DO have been consultant or investigator in clinical trials sponsored by the following pharmaceutical companies: Abbott, Alter, Chemo, Cinfa, FAES, Farmalíder, Ferrer, GlaxoSmithKline, Galenicum, Gilead, Janssen-Cilag, Kern, Normon, Novartis, Servier, Silverpharma, Teva and Zambon. The other authors declare that they have no conflicts of interest.